Climate Change and Global Warming

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1 Climate Change and Global Warming

2 What is the difference between weather and climate? Weather Weather refers to general day-to-day temperatures, precipitation and air activities. For example: - Today is it warm and sunny with a slight north-easterly blowing. - Tomorrow will be cold with a temperature of 11 degrees Celsius accompanied by a 55% chance of rainfall in the late afternoon. Climate Climate refers to weather patterns that are recorded over a period of time. For example: longer - The Western Cape has a climate with hot, dry summers and cold, wet winters. - The Eastern Cape enjoys hot, wet summers and moderate, dry winters.

3 Climate change is the long - term change in the weather patterns that s noticed anywhere between a decade to billions of years. It either occurs to a specific area or worldwide. The most important and severe cause of climate change is GLOBAL WARMING.

4 THE GREENHOUSE EFFECT Life on earth depends on energy from the sun A small amount of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet's surface and is reflected upward again as a type of slow-moving energy called infrared radiation. Either one of two things will then happen to this heat: 1. It is released through the atmosphere back into space. 2. It is absorbed by greenhouse gases, such as water vapour, carbon dioxide, nitrogen dioxide, methane and CFC s.

5 This absorbed heat is now trapped and held in a kind of warm-air blanket that surrounds the planet, and it keeps our planet warm. This phenomenon is what scientists call the greenhouse effect." This is a natural phenomenon that is necessary to keep our climates balanced Without it, scientists estimate that the average temperature on Earth would be colder by approximately 30 degrees Celsius, far too cold to sustain our current ecosystem.

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7 GLOBAL WARMING An increase in temperature causing in the earth s climate to get warmer. What causes global warming? Many greenhouse gases occur naturally and are needed to create the greenhouse effect that keeps the Earth warm enough to support life, BUT human activities are causing there to be a considerable increase in greenhouse gases especially carbon dioxide. This in turn, leads to more heat being trapped and absorbed in our atmosphere, therefore resulting in global warming.

8 Humans are cause for the increased release of carbon dioxide and other greenhouse gases by: 1. Burning fossil fuels (oil, wood, coal): driving cars (petrol) using electricity from coal-fired power plants (coal) heating our homes with oil or natural gas (oil/gas/wood) 2. Deforestation 3. Population Growth

9 CONSEQUENCES of Global Warming This increase in trapped heat changes the climate and alters weather patterns...which may lead to the following:

10 1. Many of the world s endangered species would become extinct as rising temperatures changed their habitat. 2. Change in the length of the seasons. 3. Lead to more frequent and severe storms. 4. Certain diseases carried by animals or insects, such as malaria, would become more widespread as warmer conditions expanded their range. 5. Rising sea levels, which would reduce supplies of fresh water as flooding occurs along coastlines worldwide and salt water reaches inland.

11 Normal Conditions: El Nino 1. Strong easterly winds blow across the Pacific Ocean. 2. Therefore, the winds drag surface water westerly. 3. Deeper, colder water then rises to the surface, off the west coast of South America (Eastern side of the Pacific Ocean). 4. Rain falls on the eastern side of Australia (western side of the Pacific Ocean). 5. The warm water near causes upward airflow leading to low pressure, therefore causing water vapour to rise upwards and fall as rain 6. Air subsides of the west coast of South America (cold water results in high pressure), causing dry weather.

12 El Nino (continued) El Nino Conditions: 1. During El Nino, the easterly winds weaken significantly. 2. Warm water does not reach the east coast of Australia. 3. Less deeper, colder water is brought to the surface in the east Pacific Ocean, resulting in warmer water than usual. 4. The warmer water, which is usually found over the west Pacific Ocean (east coast side of Australia), is now found in the central Pacific. Therefore, the rainfall is also higher in the central Pacific. 5. Australia experiences cooler water compared to normal, thus the air pressure is high and conditions are drier. 6. The coast of South America experiences warm waters, effecting the distribution of fish for fishermen and causing more rain than normal. 7. The main result of El Nino, is that some places receive more rain than normal, while other places have much less rain than normal. 8. South Africa receives less rain than normal, often leading to drought.